Tribology and Micromechanics of Chromium Nitride Based Multilayer Coatings on Soft and Hard Substrates

Abstract

Abstract:The tribological protection of carbon fiber reinforced epoxy composites (CFC) is essential for broadening their use from structural to functional applications, e.g., to linear bearings in mechanical engineering. However, their wear resistance in sliding and rolling contacts is low. This work focusses on the possibility of improving their tribological properties by the application of thin hard multi-layered coatings. Chromium nitride (CrN) single layer and chromium-CrN multilayer coatings of ~4 µm thickness, partly finished with a 1 µm diamond-like carbon (DLC) top layer, were deposited by magnetron sputtering at low temperatures on soft CFC and for comparison of the mechanical behavior on comparatively hard austenitic steel substrates. Structural investigations showed especially that the multilayer coatings possess a very fine grained, columnar microstructure and a very low density of intercolumnar micro-cracks, while the single layer coatings possess a coarse structure. The indentation testing and the analysis of the deformed and fractured cross-sections revealed a tougher behavior with improved plastic deformability of the multilayers in comparison to CrN single layers. However, in wear testing only coatings with DLC top layers significantly improved the tribological material properties of CFC. This is due to the reduced shear forces in sliding on low-friction DLC coatings on the soft OPEN ACCESSCoatings 2014, 4 122 epoxy-based CFC, decreasing the total dynamic stresses during sliding under high loads.

Erosion and Toughening Mechanisms of Electroless Ni-P-Nano-NiTi Composite Coatings on API X100 Steel under Single Particle Impact

“…Hertzian-type cracks form on the surface just outside the contact area where the radial stress reaches its maximum tensile value [38] [39]. Radial cracks also develop on the surface but are caused by the maximum tensile hoop stress [40]. Hoop stress becomes positive (tension) on the surface during elastic-plastic contact which applies to the present study [41].…”

A study of the effect of deposition conditions on the phase-structural state of ion-plasma WC – TiC coatings

“…As a result, it was possible to expand the areas of temperature and concentration stabilization of phase-structural states [8,9]. This allowed us to create new types of materials with high functional properties [10,11]. The highest mechanical properties were achieved for systems including silicon [12,13].…”

Target Voltage Hysteresis Behavior and Control Point in the Preparation of Aluminum Oxide Thin Films by Medium Frequency Reactive Magnetron Sputtering

“…As a surface protective coating for highly active metals, aluminum oxide film bears substantial potential to enhance the wear and corrosion resistance of metal surfaces by forming multilayered aluminum/aluminum oxide coatings, with the possible merits of higher density, better adhesion properties, and lower residual stress than the two single layer coatings alone [1,2,6,7]. In this work we report our investigations on the preparation of aluminum oxide thin films deposited by reactive magnetron sputtering, which is a common technique in the preparation of compound thin films and coatings.…”